Certainty and conviction in the Afterlife

ٱلَّذِينَ يُقِيمُونَ ٱلصَّلَوٰةَ وَيُؤْتُونَ ٱلزَّكَوٰةَ وَهُم بِٱلْـَٔاخِرَةِ هُمْ يُوقِنُونَ

Who establish prayer and give zakāh, and they, of the Hereafter, are certain [in faith].